CN100542663C - A permanent magnet rotating stirring device - Google Patents

Abstract

The invention provides a permanent magnet rotating stirring device, comprising a closed container (4) with a magnetic ionic liquid (10) inside, and the center of the bottom of the container (4) is provided with an inwardly protruding central magnet groove (19), A first permanent magnet (5) located in the central magnet groove (19), and a rotary motor (6) that drives the first permanent magnet (5) to rotate in the central magnet groove (9), is characterized in that , the bottom of the container (4) is also provided with at least one circular magnet groove, and at least one is located in the circular magnet groove, which can be driven by the rotating motor (6) along the circular magnet. The second permanent magnet (22) that groove rotates, and the magnetic pole direction of described second permanent magnet (22) is identical with first permanent magnet (5); The present invention overcomes the magnetic ionic liquid in existing permanent magnet rotating stirring device The defect that the rotational power is reduced due to the decrease of the magnetic force due to the increase of the distance from the permanent magnet.

Description

A permanent magnet rotating stirring device

technical field

The invention relates to a stirring device, in particular to a permanent magnet rotating stirring device with a magnetic ionic liquid as a medium.

technical background

The magnetically stabilized bed is a gas-liquid reactor researched for the application of magnetic catalysts. That is, several sets of fixed coils are added outside the reactor. When the current passes through the coils, a magnetic field is generated, and the magnetic catalyst particles are arranged regularly under the action of the magnetic field. The bubbles in the reactor have the effect of breaking and cutting, and the magnetic particle catalyst will not be taken out of the reactor with the high-speed flow of the reaction medium and lost. At the same time, the magnetic catalyst can be recovered by using the magnetic field. The magnetically stabilized bed has achieved satisfactory results in the industry, and its superiority has been shown in the hydrofining process of caprolactam with a treatment capacity of 70kt. Compared with the continuous stirring tank commonly used in industry, the volume is reduced from 10m ³ to 1.8m ³ , and the production quality is greatly improved. However, because the distribution of the magnetic field inside the reactor is uneven, the magnetic field attenuates inversely proportional to the square of the distance from the outer wall of the reactor to the center, resulting in uneven gas distribution, a low central magnetic field, and a concentration of magnetic particles lower than that near the inner wall of the reactor. Therefore, the bubbles will gather to the center, and at the same time, condensation will occur, which will reduce the utilization rate of the gas. For this reason, a new type of magnetic reactor has been developed, and a coil is added outside the reactor. When energized, a rotating magnetic field will be generated to make the magnetic particles inside the reactor rotate, which greatly changes the distribution of bubbles and the state of liquid flow. . But this research is still in a small stage and has not yet been scaled up and applied industrially.

Ionic liquids are substances that are liquid at room temperature and adjacent temperatures, and are composed of asymmetric organic cations and organic or inorganic anions. Common ionic liquids include hydrophobic ionic liquid [bmim]PF ₆ , hydrophilic ionic liquid [bmim]BF ₄ , [bmim]Cl, etc. Ionic liquids have the advantages of less pollution, less toxicity, strong solubility, low volatility, strong thermal stability, adjustable structure, and easy recovery. They are new green solvents and are widely used in the absorption and extraction of many gases.

Magnetic ionic liquid is a special substance. In recent years, Japan’s Hayashi et al. found that the hydrophobic [bmim]Cl can be obtained by mixing the hydrophilic ionic liquid [bmim]Cl with FeCl ₃ 6H ₂ O or FeCl ₃ in N ₂ environment. ]FeCl ₄ , this ionic liquid can strongly sense magnetic fields and has paramagnetism (Chem. Lett., Vo1.33, 1590-1591, 2004).

In the Chinese patent application (application number: 200610089480.9) titled "Extraction Device with Rotating and Stable Magnetic Stirring and Its Operation Method", a magnetically agitated dispersing method using a magnetically functional hydrophobic ionic liquid as an extractant is disclosed. The extraction device of the system includes a reaction tank whose bottom middle part is concave inward, and there is a vertical circular NdFeB permanent magnet connected with the shaft of the rotating motor in the groove; on the lower side of the reaction tank A magnetic ionic liquid outlet is opened on the wall of the reactor, a magnetic ionic liquid inlet and a feed liquid inlet are opened on the wall on the other side, and a magnetically stable bed coil is installed on the outer wall of the upper part of the reactor; in the reactor, a circular distribution The liquid inlet of the device is connected to the feed liquid inlet; the magnetically stable bed coil controls the mutual collision and condensation of the magnetic ionic liquid droplets in the dispersed phase; however, the magnetic field in the reaction tank of the device increases with the distance from the permanent magnet. The increase of , attenuated by the square, caused the uneven distribution of the magnetic field in the reaction tank, the magnetic force decreased, and the rotational power decreased.

Contents of the invention

The purpose of the present invention is to overcome the defect that the magnetic force of the magnetic ionic liquid in the existing permanent magnet rotating stirring device decreases due to the increase of the distance from the permanent magnet, thereby reducing the rotational power, thereby providing a permanent magnet rotating stirring device.

A permanent magnet rotary stirring device provided by the present invention comprises a closed container 4 with a magnetic ionic liquid 10 inside, and the center of the bottom of the container 4 is provided with a central magnet groove 19 protruding into the container 4, one located at the bottom of the container 4 The first permanent magnet 5 in the central magnet groove 19, and the rotary motor 6 that drives the first permanent magnet 5 to rotate in the central magnet groove 19, is characterized in that, the bottom of the container 4 is also provided with at least one direction to the container 4 The inner protruding circular magnet groove, and at least one second permanent magnet 22 that is positioned in the circular magnet groove and can rotate along the circular magnet groove driven by the rotating motor 6, and the The magnetic pole direction of the second permanent magnet 22 is the same as that of the first permanent magnet 5 .

Further, in the above device, the bottom of the container 4 is also provided with at least one annular gas distributor, the annular gas distributor is a circular hollow tube, and its air inlet passes through the gas path and the gas in the container 4. The inlet is connected, and at least one hole is provided on the wall of the annular gas distributor as a gas distribution hole 15 .

Further, the center of the annular gas distributor is located at the center of the bottom of the container 4 .

Further, the circular magnet groove is centered on the central magnet groove 19 .

Further, the permanent magnet is an NdFeB permanent magnet, and the magnetic field strength is 1000-3000 Oersted.

Further, the rotating speed of the rotating motor 6 is less than 300 rpm.

Further, the magnetic ionic liquid 10 is [bmim]FeCl ₄ .

The synthesis method of magnetic ionic liquid [bmim]FeCl ₄ is as follows: equimolar FeCl ₃ 6H ₂ O or FeCl ₃ and ionic liquid [bmim]Cl are mixed under nitrogen atmosphere to produce magnetic ionic liquid [bmim]FeCl ₄ (Chem.Lett ., Vol.33, 1590-1591, 2004).

The advantages of the present invention are as follows:

1. Multiple permanent magnets are used for rotating stirring, which overcomes the defect that the magnetic force of the magnetic ionic liquid in the existing permanent magnet rotating stirring device decreases due to the increase of the distance from the permanent magnet, which reduces the rotational power;

2. Use paramagnetic magnetic ionic liquid, adopt rotating magnetic field, use permanent magnet at the bottom to provide rotating magnetic field stirring, there is circulation disturbance at the bottom of the equipment, and gradually drive the entire magnetic ionic liquid to rotate, promote the dispersion of solute in the absorbent, and accelerate the absorption rate ;

3. With the paramagnetic magnetic ionic liquid as the absorbent, the absorption device made by the magnet rotating stirring device of the present invention avoids the use of traditional volatile organic solvents. Experiments show that the saturated vapor pressure of the magnetic ionic liquid is almost zero .

4. The magnet is isolated from the absorption system to avoid direct contact with the substances in the system, and it is easy to realize the airtightness of the system during the high-pressure absorption process;

5. Using a permanent magnet to stir the magnetic ionic liquid, the shear force is low, and it is suitable for systems containing biologically active substances;

6. The permanent magnet stirring requires less electricity, and the motor speed regulation power is smaller than that of the stirring paddle, and the power is far lower than that of the conventional stirring device, which greatly reduces the energy consumption of the process.

Description of drawings

Fig. 1 measures the schematic diagram of the measurement system of the absorption capacity of magnetic ionic liquid to benzene;

The schematic diagram of the bottom of the container of the permanent magnet rotating stirring device of Fig. 2a;

Figure 2b schematic diagram of the annular gas distributor;

Fig. 3 The absorption curve of magnetic ionic liquid to benzene vapor.

reference sign

1. Nitrogen cylinder 2. Gas flow meter 3. Solute storage tank

4. Container 5. First permanent magnet 6. Rotary motor

7. The first annular gas distributor 8. The magnet connecting shaft 9. The second annular gas distributor

10. Magnetic ionic liquid 11. Third annular gas distributor 12. Gas outlet

13. Liquid nitrogen cold trap 14. Vacuum pump 15. Gas distribution hole

18. Second ring magnet groove 19. Central magnet groove 20. First ring magnet groove

22. The second permanent magnet 23. The third permanent magnet 24. The fourth permanent magnet

25. The fifth permanent magnet 26. The third gas path 27. The first gas path

28. The second gas path

Detailed ways

The present invention will be further explained and illustrated below in conjunction with specific embodiments.

As shown in Figure 1, the system for measuring the absorption of benzene vapor by magnetic ionic liquids adopts the permanent magnet rotating stirring device of the present invention, and the nitrogen cylinder 1 is connected to the bottom of the solute storage tank 3 through the first gas path 27, and the first gas A gas flowmeter 2 is arranged on the road, and the upper part of the solute storage tank 3 is respectively connected to the first, second and third annular gas distributors 7, 9, 11 through the second gas passage 28, and the first, second and third Annular gas distributors 7, 9, 11 are fixed to the bottom of the cylindrical container 4 and placed concentrically, as shown in Figure 2b and Figure 2a, the bottom of the container 4 except for the central position has one for accommodating the first permanent magnet Outside the center magnet groove 19 of 5, also be provided with two first and second annular magnet grooves 20,18 centered on the center magnet groove 19, the first permanent magnet 5 is centered on the magnet connecting shaft 8 respectively The second and third permanent magnets 22,23 are fixed symmetrically, and the fourth and fifth permanent magnets 24,25, and the first permanent magnet 5 is installed in the central magnet groove 19, and the second and third permanent magnets 22,23 Installed in the first annular magnet groove, the fourth and fifth permanent magnets 24, 25 are installed in the second annular groove, the five permanent magnets are all vertical cylindrical NdFeB permanent magnets, and the magnetic field strength is 1000-3000 Oster; the rotary motor 6 can drive the magnet connection shaft 8 to rotate around the axis of the cylindrical container 4, so that the five vertical cylindrical NdFeB permanent magnets fixed on it rotate in their respective magnet grooves , to achieve the purpose of rotating the magnetic field, the rotating speed of the rotating motor 6 is less than 300 rpm; the upper part of the side wall of the container 4 is provided with a gas outlet 12, and is connected to the inlet of the liquid nitrogen cold trap 13 through the third gas path 26, the liquid nitrogen The outlet of nitrogen cold trap 13 is connected with vacuum pump 14.

The steps of using the above system to measure the absorption of benzene vapor by magnetic ionic liquid are as follows:

1. Put 10ml of magnetic ionic liquid [bmim]FeCl ₄ in the container 4; turn on the vacuum pump 14, and stop the vacuum pump 14 after the vacuum degree reaches 10 ^-5 Pa;

2. Start the rotary motor 6, and adjust the number of revolutions to be 0, 7.5 revolutions/minute, 12 revolutions/minute and 17 revolutions/minute;

3. Turn on the nitrogen bottle 1, adjust the flow rate to 80ml/min, nitrogen is used as the carrier gas to bring the volatile gas of benzene in the solute storage tank 3 into the magnetic ion through the first, second and third annular gas distributors 7, 9, 11 For liquid 10, weigh the mass of liquid benzene condensed by liquid nitrogen cold trap 13 and the mass of benzene reduced in solute storage tank 3 at different absorption times, and calculate the absorption curve and saturation of magnetic ionic liquid 10 for benzene vapor in different time The absorption capacity is shown in the curve in Figure 3.

The permanent magnet rotating stirring device of the present invention can be used in an absorption device, and can also be used in reaction processes such as extraction with a magnetic ionic liquid as a medium. In addition, Embodiment 1 has adopted two circular magnet grooves, each circular Two permanent magnets are arranged symmetrically in the ring magnet groove, and according to the size of the container, more ring magnet grooves or only one ring magnet groove can be used; each ring magnet groove Only one, or two, three, or even more permanent magnets can be set in the slot to further increase the magnetic field strength and uniformity, and the N poles of all permanent magnets are set in the same direction, specific to the above implementation Example 1 is that the N poles of the first to fifth permanent magnets in Fig. 1 are all facing up or all facing down.

Claims (6)

1. permanent-magnet gyratory agitation device, comprise that inside is equipped with the closed container of magnetic ion liquid (10) (4), and container (4) bottom centre is provided with the center magnet groove (19) to inner process, one is positioned at first permanent magnet (5) of described center magnet groove (19), and drive the rotation motor (6) that first permanent magnet (5) rotates in center magnet groove (19), it is characterized in that, described container (4) bottom also is provided with at least one annular magnet groove to container (4) inner process, be positioned at described annular magnet groove with at least one, can drive second permanent magnet (22) that lower edge described annular magnet groove rotates at rotation motor (6), and the pole orientation of described second permanent magnet (22) is identical with first permanent magnet (5); The center of circle of described annular gas distributor is positioned at the bottom centre position of described container (4).

2. by the described permanent-magnet gyratory agitation device of claim 1, it is characterized in that, bottom in the described container (4) also is provided with at least one annular gas distributor, described annular gas distributor is the annular hollow tube, its air inlet is communicated with by the gas access of gas circuit with container (4), and described annular gas distribution wall is provided with at least one hole as distribution of gas hole (15).

3. by the described permanent-magnet gyratory agitation device of claim 1, it is characterized in that described annular magnet groove is the center with center magnet groove (19).

4. by the described permanent-magnet gyratory agitation device of claim 1, it is characterized in that described permanent magnet is a Nd-Fe-B permanent magnet, magnetic field intensity is 1000-3000 oersteds.

5. by the described permanent-magnet gyratory agitation device of claim 1, it is characterized in that the rotating speed of described rotation motor (6) is less than 300 rev/mins.

6. by the described permanent-magnet gyratory agitation device of claim 1, it is characterized in that described magnetic ion liquid (10) is [bmim] FeCl ₄

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